Anadarko Discovers Oil Offshore Sierra Leone

HOUSTON, TX -- (Marketwire) -- 11/15/10 -- Anadarko Petroleum Corporation (NYSE: APC) today announced the Mercury-1 exploration well offshore Sierra Leone encountered approximately 135 net feet of oil pay in two Cretaceous-age fan systems. Mercury is the company's second deepwater test in the Sierra Leone-Liberian Basin and was drilled to a total depth of approximately 15,950 feet in about 5,250 feet of water.

'The Mercury well demonstrates that the stratigraphic trapping systems we've identified are working, and that the petroleum system is generating high-quality oil,' Anadarko Sr. Vice President, Worldwide Exploration Bob Daniels said. 'In the primary objective, the Mercury well encountered approximately 114 net feet of light sweet crude oil with a gravity of between 34 and 42 degrees API, with no water contact. An additional 21 net feet of 24-degree gravity crude was encountered in a shallower secondary objective.

'These results continue to build momentum in the basin and enhance our confidence in the team's seismic interpretation and geologic modeling,' added Daniels. 'We are preserving the wellbore for potential re-entry, DST (drillstem testing) or a down-dip sidetrack to further delineate the reservoir's areal extent, quality and deliverability. We also plan to continue working with the government of Sierra Leone and our partnership to accelerate exploration and appraisal activity in the area in 2011.'

The Mercury discovery is located in offshore block SL-07B-10 approximately 40 miles east-southeast of Anadarko's previously announced Venus discovery. Anadarko holds an interest in more than 4.6 million acres on five deepwater blocks offshore Sierra Leone and Liberia, and has identified more than 17 prospects and leads on 3-D seismic on this acreage. Once operations are complete at the Mercury well, the company has committed to mobilize the drillship to Ghana to accelerate the appraisal program at the Owo and Tweneboa fields, which the company anticipates sanctioning in 2011.

Anadarko operates block SL-07B-10 with a 65-percent working interest. Co-owners in the block include Repsol Exploracion Sierra Leone, S.L. (25-percent working interest) and Tullow Sierra Leone B.V. (10-percent working interest).

A map of the Mercury discovery and Anadarko's acreage position offshore Sierra Leone and Liberia will be available under the 'Media Center/Anadarko News' tab at www.anadarko.com.

Anadarko Petroleum Corporation's mission is to deliver a competitive and sustainable rate of return to shareholders by exploring for, acquiring and developing oil and natural gas resources vital to the world's health and welfare. As of year-end 2009, the company had approximately 2.3 billion barrels-equivalent of proved reserves, making it one of the world's largest independent exploration and production companies. For more information about Anadarko, please visit www.anadarko.com.

This news release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. Anadarko believes that its expectations are based on reasonable assumptions. No assurance, however, can be given that such expectations will prove to have been correct. A number of factors could cause actual results to differ materially from the projections, anticipated results or other expectations expressed in this news release, including Anadarko's ability to successfully drill, complete, test and produce these wells and prospects, or successfully sanction the projects identified in this news release. See 'Risk Factors' in the company's 2009 Annual Report on Form 10-K, Quarterly Report on Form 10-Q for the quarter ended Sept. 30, 2010 and other public filings and press releases. Readers are cautioned not to place undue reliance on forward-looking statements, which speak only as of the date hereof. Anadarko undertakes no obligation to publicly update or revise any forward-looking statements.

Image Available: http://www2.marketwire.com/mw/frame_mw?attachid=1422767

Anadarko Contacts

Media:
John Christiansen
Email Contact

832.636.8736


Matt Carmichael
Email Contact

832.636.2845

Investors:
John Colglazier
Email Contact

832.636.2306


Chris Campbell, CFA
Email Contact

832.636.8434


Dean Hennings
Email Contact

832.636.2462